1. Field of the Invention
The present invention relates generally to a key input method and apparatus in a terminal with a keypad. In particular, the present invention relates to a method and apparatus for inputting alphabet characters.
2. Description of the Related Art
In general, a mobile terminal refers to a device designed such that an individual can carry it and transmit/receive voice and data regardless of time and place. The mobile terminal is classified into a work analysis program (WAP) phone, a personal digital assistance (PDA), a web pad, and the like and is commonly used by an increasing number of people due to its ability to provide personal service-based mobility. With the development of communication technology, the mobile terminal is used not only for voice communication but also image communication. Due to the rapid progress of mobile communication technology, service providers or mobile carriers provide users with additional services in addition to the basic mobile terminal's functions of processing calls and guaranteeing the quality of the calls. For example, the additional services include a voice information service for providing users with news, sports, stock, and weather information, a traffic information service for providing users with traffic information, and a communication service such as Internet access, fax and e-mail services. In addition to the foregoing services, an increasing number of mobile terminal users are enjoying text and voice services.
In most cases, to enjoy such services, a user of the mobile terminal inputs characters using a keypad mounted on the mobile terminal. For example, to transmit a short message service (SMS) message, store phone numbers in a phone book, and transmit an e-mail via wireless Internet using the mobile terminal, the user inputs corresponding characters using the keypad. A description will now be made regarding how the user inputs alphabet characters through the existing keypad used for the mobile terminal.
FIG. 1 is a diagram illustrating a layout of a conventional keypad for a mobile terminal. As illustrated in FIG. 1, the keypad includes buttons arranged in 4 rows and 3 columns, and numbers, alphabet characters and special characters are mapped to the buttons. In one of a number mode, an alphabet character mode, and a special character mode, if the buttons are pressed, numbers or characters mapped to the pressed buttons are input. Referring to FIG. 1, in each button, a number is written in the center, and possible alphabet characters of, for example, QZ, ABC, GHI, . . . , WXY, are written under the number. As illustrated, 3 alphabet characters are allocated to most of the buttons with a number written thereon. To input a word using the keypad of FIG. 1, the user should press buttons corresponding to alphabets comprising the word a predetermined number of times as shown in Table 1.
TABLE 1No. of buttonpresses1234567891QADGJMPTW2ZBEHKNRUX3CFILOSVY
It will be assumed herein that the user inputs a word “LOVE” through the conventional keypad of FIG. 1. Referring to Table 1, the user should press a button with a number ‘5’ three times to input ‘L’, a button with a number ‘6’ three times to input ‘O’, a button with a number ‘8’ three times to input ‘V’, and a button with a number ‘3’ two times to input ‘E’.
The conventional keypad does not fully consider the convenience of the user and requires the user to press the same button several times in order to input a word. Therefore, the user feels inconvenienced especially when inputting frequently used words. For this reason, English-speaking users feel inconvenienced by the alphabet character input method because their body structure does not match well with the structure of the conventional keypad. To solve this problem, the alphabets of the conventional keypad should be appropriately rearranged. However, it is difficult to change a structure and design of products that have already been put on the market. In addition, because English-speaking users have become accustomed to the structure of the conventional keypad, it is not preferable to change the structure of the keypad. If a device for displaying all of the words starting with characters input by the user based on words in an English dictionary in the mobile terminal to solve the problems, the required memory capacity increases and the power required for outputting a specific word also increases, placing restrictions on the implementation.